mch2022-template-app/main/wifi_connection.c
2022-06-09 15:29:13 +02:00

287 lines
10 KiB
C

#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"
#include "esp_system.h"
#include "esp_event.h"
#include "esp_log.h"
#include "lwip/err.h"
#include "lwip/sys.h"
#include "wifi_connection.h"
static const char *TAG = "wifi_connection";
#define WIFI_CONNECTED_BIT BIT0
#define WIFI_FAIL_BIT BIT1
#define WIFI_STARTED_BIT BIT2
static EventGroupHandle_t wifiEventGroup;
static uint8_t retryCount = 0;
static uint8_t maxRetries = 3;
static bool isScanning = false;
#define WIFI_SORT_ERRCHECK(err) do {int res = (err); if(res) {ESP_LOGE(TAG, "WiFi connection error: %s", esp_err_to_name(res)); goto error; } } while(0)
static void event_handler(void* arg, esp_event_base_t event_base, int32_t event_id, void* event_data) {
if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START) {
xEventGroupSetBits(wifiEventGroup, WIFI_STARTED_BIT);
if (!isScanning) {
// Connect only if we're not scanning the WiFi.
esp_wifi_connect();
}
ESP_LOGI(TAG, "WiFi station start.");
} else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_STOP) {
xEventGroupClearBits(wifiEventGroup, WIFI_STARTED_BIT);
ESP_LOGI(TAG, "WiFi station stop.");
} else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED) {
if (retryCount < 3) {
esp_wifi_connect();
retryCount++;
ESP_LOGI(TAG, "Retrying connection");
} else {
ESP_LOGI(TAG, "Connection failed");
xEventGroupSetBits(wifiEventGroup, WIFI_FAIL_BIT);
}
} else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP) {
ip_event_got_ip_t* event = (ip_event_got_ip_t*) event_data;
ESP_LOGI(TAG, "Got ip:" IPSTR, IP2STR(&event->ip_info.ip));
retryCount = 0;
xEventGroupSetBits(wifiEventGroup, WIFI_CONNECTED_BIT);
}
}
void wifi_init() {
// Create an event group for WiFi things.
wifiEventGroup = xEventGroupCreate();
// Initialise WiFi stack.
ESP_ERROR_CHECK(esp_netif_init());
ESP_ERROR_CHECK(esp_event_loop_create_default());
esp_netif_create_default_wifi_sta();
wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
ESP_ERROR_CHECK(esp_wifi_init(&cfg));
// Register event handlers for WiFi.
esp_event_handler_instance_t instance_any_id;
esp_event_handler_instance_t instance_got_ip;
ESP_ERROR_CHECK(esp_event_handler_instance_register(WIFI_EVENT, ESP_EVENT_ANY_ID, &event_handler, NULL, &instance_any_id));
ESP_ERROR_CHECK(esp_event_handler_instance_register(IP_EVENT, IP_EVENT_STA_GOT_IP, &event_handler, NULL, &instance_got_ip));
// Turn off WiFi hardware.
ESP_ERROR_CHECK(esp_wifi_stop());
}
bool wifi_connect(const char* aSsid, const char* aPassword, wifi_auth_mode_t aAuthmode, uint8_t aRetryMax) {
// Set the retry counts.
retryCount = 0;
maxRetries = aRetryMax;
// Create a config.
wifi_config_t wifi_config = {0};
strcpy((char*) wifi_config.sta.ssid, aSsid);
strcpy((char*) wifi_config.sta.password, aPassword);
wifi_config.sta.threshold.authmode = aAuthmode;
// Set WiFi config.
WIFI_SORT_ERRCHECK(esp_wifi_set_mode(WIFI_MODE_STA));
WIFI_SORT_ERRCHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_config));
// Disable 11b as NOC asked.
esp_wifi_config_11b_rate(WIFI_IF_STA, true);
// Start WiFi.
WIFI_SORT_ERRCHECK(esp_wifi_start());
ESP_LOGI(TAG, "Connecting to WiFi...");
/* Waiting until either the connection is established (WIFI_CONNECTED_BIT) or connection failed for the maximum
* number of re-tries (WIFI_FAIL_BIT). The bits are set by event_handler() (see above) */
EventBits_t bits = xEventGroupWaitBits(wifiEventGroup, WIFI_CONNECTED_BIT | WIFI_FAIL_BIT, pdFALSE, pdFALSE, portMAX_DELAY);
/* xEventGroupWaitBits() returns the bits before the call returned, hence we can test which event actually happened. */
if (bits & WIFI_CONNECTED_BIT) {
ESP_LOGI(TAG, "Connected to WiFi");
return true;
} else if (bits & WIFI_FAIL_BIT) {
ESP_LOGE(TAG, "Failed to connect");
WIFI_SORT_ERRCHECK(esp_wifi_stop());
} else {
ESP_LOGE(TAG, "Unknown event received while waiting on connection");
WIFI_SORT_ERRCHECK(esp_wifi_stop());
}
error:
return false;
}
bool wifi_connect_ent(const char* aSsid, const char *aIdent, const char *aAnonIdent, const char* aPassword, esp_eap_ttls_phase2_types phase2, uint8_t aRetryMax) {
retryCount = 0;
maxRetries = aRetryMax;
wifi_config_t wifi_config = {0};
if (strlen(aSsid) > 32) {
ESP_LOGE(TAG, "SSID is too long (%zu > 32)!", strlen(aSsid));
return false;
}
strncpy((char*) wifi_config.sta.ssid, aSsid, 32);
// Set WiFi config.
WIFI_SORT_ERRCHECK(esp_wifi_set_mode(WIFI_MODE_STA) );
WIFI_SORT_ERRCHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_config) );
// Set WPA2 ENT config.
WIFI_SORT_ERRCHECK(esp_wifi_sta_wpa2_ent_set_identity((const uint8_t *) aAnonIdent, strlen(aAnonIdent)));
WIFI_SORT_ERRCHECK(esp_wifi_sta_wpa2_ent_set_username((const uint8_t *) aIdent, strlen(aIdent)));
WIFI_SORT_ERRCHECK(esp_wifi_sta_wpa2_ent_set_password((const uint8_t *) aPassword, strlen(aPassword)));
WIFI_SORT_ERRCHECK(esp_wifi_sta_wpa2_ent_set_ttls_phase2_method(phase2));
// Enable enterprise auth.
WIFI_SORT_ERRCHECK(esp_wifi_sta_wpa2_ent_enable());
// Disable 11b as NOC asked.
WIFI_SORT_ERRCHECK(esp_wifi_config_11b_rate(WIFI_IF_STA, true));
// Start the connection.
WIFI_SORT_ERRCHECK(esp_wifi_start());
ESP_LOGI(TAG, "Connecting to '%s' as '%s'/'%s': %s", aSsid, aIdent, aAnonIdent, aPassword);
ESP_LOGI(TAG, "Phase2 mode: %d", phase2);
/* Waiting until either the connection is established (WIFI_CONNECTED_BIT) or connection failed for the maximum
* number of re-tries (WIFI_FAIL_BIT). The bits are set by event_handler() (see above) */
EventBits_t bits = xEventGroupWaitBits(wifiEventGroup, WIFI_CONNECTED_BIT | WIFI_FAIL_BIT, pdFALSE, pdFALSE, portMAX_DELAY);
/* xEventGroupWaitBits() returns the bits before the call returned, hence we can test which event actually happened. */
if (bits & WIFI_CONNECTED_BIT) {
ESP_LOGI(TAG, "Connected to WiFi");
return true;
} else if (bits & WIFI_FAIL_BIT) {
ESP_LOGE(TAG, "Failed to connect");
WIFI_SORT_ERRCHECK(esp_wifi_stop());
} else {
ESP_LOGE(TAG, "Unknown event received while waiting on connection");
WIFI_SORT_ERRCHECK(esp_wifi_stop());
}
error:
return false;
}
// Shows a nice info message describing an AP record.
static inline void wifi_desc_record(wifi_ap_record_t *record) {
// Make a string representation of BSSID.
char *bssid_str = malloc(3*6);
if (!bssid_str) return;
snprintf(bssid_str, 3*6, "%02X:%02X:%02X:%02X:%02X:%02X",
record->bssid[0], record->bssid[1], record->bssid[2],
record->bssid[3], record->bssid[4], record->bssid[5]
);
// Make a string representation of 11b/g/n modes.
char *phy_str = malloc(9);
if (!phy_str) {
free(bssid_str);
return;
}
*phy_str = 0;
if (record->phy_11b | record->phy_11g | record->phy_11n) {
strcpy(phy_str, " 1");
}
if (record->phy_11b) {
strcat(phy_str, "/b");
}
if (record->phy_11g) {
strcat(phy_str, "/g");
}
if (record->phy_11n) {
strcat(phy_str, "/n");
}
phy_str[2] = '1';
ESP_LOGI(TAG, "AP %s %s rssi=%hhd%s", bssid_str, record->ssid, record->rssi, phy_str);
free(bssid_str);
free(phy_str);
}
// Scan for WiFi access points.
size_t wifi_scan(wifi_ap_record_t **aps_out) {
isScanning = true;
wifi_ap_record_t *aps = NULL;
// Scan for any non-hidden APs on all channels.
wifi_scan_config_t cfg = {
.ssid = NULL,
.bssid = NULL,
.channel = 0,
.scan_type = WIFI_SCAN_TYPE_ACTIVE,
.scan_time = { .active={ 0, 0 } },
};
// Start the scan now.
ESP_LOGI(TAG, "Starting scan...");
esp_err_t res = esp_wifi_scan_start(&cfg, true);
// Whether to call esp_wifi_stop() on finish.
bool stopWhenDone = false;
if (res == ESP_ERR_WIFI_NOT_STARTED) {
// If it complains that the wifi wasn't started, then do so.
ESP_LOGI(TAG, "Starting WiFi for scan");
// Set to station but don't connect.
res = esp_wifi_set_mode(WIFI_MODE_STA);
if (res) goto ohno;
// Start WiFi.
res = esp_wifi_start();
if (res) goto ohno;
stopWhenDone = true;
// Await the STA started bit.
xEventGroupWaitBits(wifiEventGroup, WIFI_STARTED_BIT, pdFALSE, pdFALSE, pdMS_TO_TICKS(2000));
// Try again.
res = esp_wifi_scan_start(&cfg, true);
}
if (res) {
ohno:
ESP_LOGE(TAG, "Error in WiFi scan: %s", esp_err_to_name(res));
isScanning = false;
return 0;
}
// Allocate memory for AP list.
uint16_t num_ap = 0;
WIFI_SORT_ERRCHECK(esp_wifi_scan_get_ap_num(&num_ap));
aps = malloc(sizeof(wifi_ap_record_t) * num_ap);
if (!aps) {
ESP_LOGE(TAG, "Out of memory (%zd bytes)", sizeof(wifi_ap_record_t) * num_ap);
num_ap = 0;
esp_wifi_scan_get_ap_records(&num_ap, NULL);
return 0;
}
// Collect APs and report findings.
WIFI_SORT_ERRCHECK(esp_wifi_scan_get_ap_records(&num_ap, aps));
for (uint16_t i = 0; i < num_ap; i++) {
wifi_desc_record(&aps[i]);
}
// Clean up.
if (aps_out) {
// Output pointer is non-null, return the APs list.
*aps_out = aps;
} else {
// Output pointer is null, free the APs list.
free(aps);
}
if (stopWhenDone) {
// Stop WiFi because it was started only for this scan.
esp_wifi_stop();
}
isScanning = false;
return num_ap;
error:
if (aps) free(aps);
return 0;
}
// Get the strength value for a given RSSI.
wifi_strength_t wifi_rssi_to_strength(int8_t rssi) {
if (rssi > WIFI_THRESH_VERY_GOOD) return WIFI_STRENGTH_VERY_GOOD;
else if (rssi > WIFI_THRESH_GOOD) return WIFI_STRENGTH_GOOD;
else if (rssi > WIFI_THRESH_BAD) return WIFI_STRENGTH_BAD;
else return WIFI_STRENGTH_VERY_BAD;
}